The invention relates to a lordosis support for a seat back rest, comprising a support plate that is held between two frame legs of the seat back by means of at least two tension members and has on each side at least one point of attack for the respective tension member, and an adjusting device for adjusting a tension force of the tension members.
Lordosis supports of this type are provided for example in the seat backs of automotive vehicle seats and serve to support the spine of the user in the region of the lumbar verte-brae so as to achieve a healthy seat posture. The force that the user exerts on the support plate has the effect that the support plate is pushed back and reaches a position in which it is offset rearwardly relative to the plane of the frame legs. When, now, the tension force of the tension members is increased by means of the adjusting device, the support plate is drawn closer to the plane of the frame legs, so that it is less compliant to the force of the user and, correspondingly, provides a stronger support action.
In known lordosis supports of this type, the tension force of the tension members is increased by reducing the effective length of the tension members.
For example, EP 1 190 127 B1 describes a lordosis support of the type indicated above, wherein the tension members are configured as flexible cables that are deflected, ap-proximately in the center of the support plate, in a direction in parallel with the frame legs. The ends of these cables are connected to a common connector that can be displaced in the direction in parallel with the frame legs by means of the adjusting device, whereby the effective length of the cables is changed.